This invention relates to automatic signal parameter control such as automatic gain-control and in particular, but not exclusively, to fast acting amplifier systems for burst mode transmission systems.
In the case of an optical local area network such as a number of subscribers connected by optical fibre to a local exchange, each subscriber being allocated a respective time slot for transmission, for example as in a time division multiple access (TDMA) arrangement, then simply because of the distances involved and the number of fibre splits, there will be an optical signal level difference as seen at the exchange between the signal packets received from the various subscribers. In order to achieve a high efficiency network, the time slots need to be compressed as close together as possible, so that a receiver at the exchange will see significant variations in amplitude in a very short period of time. An object of the present invention is to compensate for these variations.